A carrier-attached copper foil having good circuit formability is provided. The carrier-attached copper foil has a carrier, an intermediate layer and an ultra-thin copper layer in this order, the number of crystal grains per unit cross-sectional area of the ultra-thin copper layer in the through-thickness direction is 0.1 to 5 grains/μm2, and a ten point average roughness Rz of a surface on a side of the ultra-thin copper layer is 0.1 to 2.0 μm.